So I have never actually tried, but could you not just have multiple SSH keys in your .ssh folder and run the same command in the article telling git specifically which one to use instead of one within the git directory?
That seems like it would fix the issue here without introducing a major security issue.
To be blunt... If I was security at a company and found out someone was doing this, I would question why they have the right to use git frankly.
Edit: I should have clicked through to the superuser article which answered my question that this is perfectly fine with git and having multiple in .ssh.
So honest question... why did you think this was a necessary "twist" worth the risks of copying those files to a location it should not be?